I am getting an warning for the following code, using moment.js, in my Angular app:

moment(value).add(6, 'hours').format("MM/DD/YYYY");

The warning/error printing to the console is:

moment.js:293 Deprecation warning: value provided is not in a recognized RFC2822 or ISO format. moment construction falls back to js Date(), which is not reliable across all browsers and versions. Non RFC2822/ISO date formats are discouraged and will be removed in an uping major release. Please refer to / for more info. Arguments: [0] _isAMomentObject: true, _isUTC: false, _useUTC: false, _l: undefined, _i: Apr 10, 2007, 10:00:00 PM, _f: undefined, _strict: undefined, _locale: [object Object]

I have looked at the documentation page linked in the warning, but it's still unclear to me what I need to change to get rid of the deprecation warning. I tried, for instance, adding an empty array as a second argument:

moment(value, []).add(6, 'hours').format("MM/DD/YYYY");

...but while that gets rids of the error, I get "invalid date" printed in my view, instead of the actual date. How do I need to adjust the syntax here to get rid of the warning?

UPDATE: The value being provided is a UTC value that has been transformed using the Angular date pipe. So I am passing through two pipes: first the Angular date pipe, and then this custom pipe using moment. the full pipe code looks like this:

import { Pipe, PipeTransform } from '@angular/core';
const moment = require('moment');

@Pipe({name: 'timeZoneSync'})
export class TimeZoneSyncPipe implements PipeTransform {

    constructor() { }

    transform(value) {
        if (value) {
            return moment(value).add(6, 'hours').format("MM/DD/YYYY");
        }
    }
}

And in my view I am using the two pipes like this:

  <input class="app-input" [ngModel]="client.dob | timeZoneSync | date:'medium'"
                                (ngModelChange)="client.dob=$event" name="inputField" type="text" /> 

I am getting an warning for the following code, using moment.js, in my Angular app:

moment(value).add(6, 'hours').format("MM/DD/YYYY");

The warning/error printing to the console is:

moment.js:293 Deprecation warning: value provided is not in a recognized RFC2822 or ISO format. moment construction falls back to js Date(), which is not reliable across all browsers and versions. Non RFC2822/ISO date formats are discouraged and will be removed in an uping major release. Please refer to http://momentjs./guides/#/warnings/js-date/ for more info. Arguments: [0] _isAMomentObject: true, _isUTC: false, _useUTC: false, _l: undefined, _i: Apr 10, 2007, 10:00:00 PM, _f: undefined, _strict: undefined, _locale: [object Object]

I have looked at the documentation page linked in the warning, but it's still unclear to me what I need to change to get rid of the deprecation warning. I tried, for instance, adding an empty array as a second argument:

moment(value, []).add(6, 'hours').format("MM/DD/YYYY");

...but while that gets rids of the error, I get "invalid date" printed in my view, instead of the actual date. How do I need to adjust the syntax here to get rid of the warning?

UPDATE: The value being provided is a UTC value that has been transformed using the Angular date pipe. So I am passing through two pipes: first the Angular date pipe, and then this custom pipe using moment. the full pipe code looks like this:

import { Pipe, PipeTransform } from '@angular/core';
const moment = require('moment');

@Pipe({name: 'timeZoneSync'})
export class TimeZoneSyncPipe implements PipeTransform {

    constructor() { }

    transform(value) {
        if (value) {
            return moment(value).add(6, 'hours').format("MM/DD/YYYY");
        }
    }
}

And in my view I am using the two pipes like this:

  <input class="app-input" [ngModel]="client.dob | timeZoneSync | date:'medium'"
                                (ngModelChange)="client.dob=$event" name="inputField" type="text" /> 

• javascript
• angular
• date
• momentjs

• 2 looks like the date value you provide to moment is not under the ISO or RFC2822 format. – Ringo Commented Jan 12, 2018 at 18:09
• What is value? Can you share that, seems like that's where the issue is – StudioTime Commented Jan 12, 2018 at 18:11
• 2 What exactly has surprised you? date:'medium' does not produce either of the required formats. Why are you even using it; why take a date then format it to a string then parse it back to a date then format it to a string again? – jonrsharpe Commented Jan 12, 2018 at 18:16
• 2 @jonsharpe To answer your question, I want the date in a reader-friendly format. So the date pipe takes 1981-09-24T05:00:00.000Z and gives me a user friendly format. But then I use moment to add hours to the date to resolve timezone sync issues. – Rey Commented Jan 12, 2018 at 18:56
• 1 "to resolve timezone sync issues" - now this seems like an XY problem, because just adding a fixed offset isn't how to deal with localising datetimes. The accepted answer doesn't solve that problem; look into e.g. Moment Timezone. And yes, it is exasperating to see someone apparently ignore the error message they've posted and not think through what the code they've written actually does; if nothing else, because that's precisely what you're supposed to do as part of creating a minimal reproducible example. Also SO will autoplete my actual username. – jonrsharpe Commented Jan 14, 2018 at 11:25

1 Answer 1

You have a link in your error message. It indirectly leads you to this: https://github./moment/moment/issues/1407

Quote:

moment construction using a non-iso string is deprecated. What this means is you can safely do

moment("2014-04-25T01:32:21.196Z"); // iso string, utc timezone

moment("2014-04-25T01:32:21.196+0600"); // iso string with timezone

moment("2014 04 25", "YYYY MM DD"); // string with format

but you can't do reliably (therefore its being deprecated)

moment("2014/04/25");

moment("Thu Apr 24 2014 12:32:21 GMT-0700 (PDT)");

moment("some random string that looks like date");

Basically, whatever provides the value to your TimeZoneSyncPipe is not doing a good job making sure that the date is in the ISO or RFC2822 format.

More specifically

'mediumDate' argument is equivalent to 'MMM d, y' (e.g. Jun 15, 2015) which is not even close to ISO.

FIX

Try using something like "client.dob | date:'yyyy-MM-ddTHH:mm:ss.sssZ' | timeZoneSync"

Forest behind the trees

@jonrsharpe is very right! My answer explains the "why" you see the error. But Jon asks a better question. Why keep translating date -> string -> date!?

Example

const parsedDate = moment("1981-09-24T05:00:00.000Z");
console.log(parsedDate.format("YYYY/MM/DD"));

Plunkr